#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {
        let result = 2 + 2;
        assert_eq!(result, 4);
    }
}


pub mod front_of_house {
    pub mod hosting {
        pub fn add_to_waitlist() {
            println!(" add_to_waitlist() invoke !")
        }

    }

    mod serving {
        fn take_payment() {
            println!(" take_payment() invoke !")
        }
    }
}


